After my last post on Bayesian bootstrap I got a question why the sample from Dirichlet distribution is taken as weights for calculating mean in the procedure and not as weights used for sampling from the original data set. Actually this mistake i...
Bootstrapping is a very popular statistical technique. However, its Bayesian analogue proposed by Rubin (1981) is not very common. I was looking for an example of its implementation in GNU R and could not find one so I decided to write a snippet presen...
Recently I wanted to reproduce Figure 2 from Watts and Strogatz (1998). The task using igraph is simple but an interesting task was annotation of the resulting plot.Watts-Strogatz model generates graphs that have so called small-world ne...
Last week I have posted about using simulation metamodeling to verify results of analytical solution of the model. After posting it I realized that the solution presented there can be improved by using knowledge of simulation model struc...
I am one of the organizers of ESSA2013 conference that will take place in September 2013 in Warsaw, Poland. The conference scope is social simulation and in particular methods of statistical analysis of simulation output (metamodeling). As we have just issued Call for Papers for the conference so I decided to post a simple example of a metamodel.
Recently I had...
When producing regression or classification trees (standard rpart or ctree from party package) in GNU R I am often unsatisfied with the default plots they produce. One of many possible solutions is to export a tree plot to Asymptote.The ...
Recently I have discussed with my friend from WLOG Solutions an implementation of banking cash management engine in GNU R. The code made a nice use of S4 classes so I thought it would be worth showing as an example.The problemEvery commercial bank need...
Since I have a vacation this time I decided to implement some entertaining graphics. I have chosen to animate a Cassini oval.The task is can be accomplished using polar equation:The implementation of the animation is given by the following code:library...
In my last post I have discussed how to work around GNU R scoping rules using environment function. This time let us look at a practical example using recode function from car package.First let us look at how&nbs...
By design GNU R uses lexical scoping. Fortunately it allows for at least two ways to simulate dynamic scoping.Let us start with the example code and next analyze it:x <- "global"f1 <- function() cat("f1:", x, "\n")f2 <- function() cat("f2:", e...
Zero Inflated Models and Generalized Linear Mixed Models with R.
Zuur, Saveliev, Ieno (2012).
